This invention relates to reciprocating engines and, more specifically, to improved compression seals, i.e., piston rings, employed in such engines.
In various types of reciprocating engines, there frequently arises a need for the cooling of compression seals, i.e., piston rings, to preclude the same from operating at such high temperatures that the viscosity of lubricating oil would be decreased to the point where scuffing would occur. In other words, where piston rings, during the operation of a reciprocating engine, attain undesirably high temperatures, the lubricating oil film thickness is decreased rendering lubrication inadequate.
Heretofore, where piston rings have required cooling, it has been accomplished by cooling the piston carrying the ring, cooling the cylinder against which the ring bears, or both. This approach is undesirable in that it can easily result in overcooling the engine, thereby increasing the rate of heat rejection to the coolant. As a consequence, less energy can be converted to useful work and a larger radiator is required. Moreover, the approach leads only to marginal cooling of the ring itself.